Light emitting diode (LED) is widely used for displaying information and messages. LED is a solid-state device that converts electric energy to light. LED display panels provide a higher level of brightness and greater optical efficiency as compared to other types of display panels. Recently, LED display panels have been used to make large indoor or outdoor display panels and televisions.
The design, fabrication, and operation of a large LED display panel face numerous technical challenges. For example, the size of an LED display panel can be as large as around 7.35 m×4.1 m. With such large display panels, it becomes difficult to send a set of data to designated LED drivers across the LED display panels in a synchronous manner. The set of data can include configuration control bits and pulse-code modulation (PCM) data. Such data control the brightness, color depth, and on-and-off of the LED display.
FIG. 1A is a schematic block diagram of an LED system 1 having a plurality of receiver cards 13, each of the receiver cards 13 being connected to a plurality of LED drivers 14. Referring to FIG. 1, the LED system 1 includes a video source 10, a SendBox 12, a plurality of receiver cards 13, and a plurality of LED drivers 14. To transmit a set of data to a designated set of LED drivers 14, the LED system 1 requires the SendBox 12 and the plurality of receiver cards 13. Depending on the configuration of the LED system, the total number of receiver cards 13 may vary. A receiver card 13 receives data from the SendBox 12 via a gigabit Ethernet port 11. A set of LED drivers 14 have access to a serially arranged set of plurality of receiver cards 13 to read the data. Each set of LED drivers 14 corresponds to a receiver card 13. Thus, as the number of LED drivers 14 grows, the number of gigabit Ethernet ports 11 designated to the plurality of receiver cards 13 increases.
FIG. 1B is a schematic block diagram of a receiver card 13a connected to another receiver card 13b and the two receiver cards connected to a set of LED drivers 14a and 14b, respectively. The diagram is an enlargement of two receiver cards 13 and the connected set of LED drivers 14 shown in FIG. 1A. It is a close-up depiction of two linked receiver cards. All other receiver cards in a serially arranged plurality of receiver cards are configured in the manner showing in FIG. 1B. The two receiver cards are connected via a GigaPHY (hereafter “GPHY”) link which requires gigabit Ethernet ports and transformers on both the sending and the receiving end of the receiver cards. As the number of receiver cards grows, the number of GPHY links between the receiver cards increases. Furthermore, each of the receiver cards requires a memory for pixel mapping. Referring to FIG. 1B, a receiver card 13a is realized by a field-programmable gate array (FPGA) device with on-board frame buffer for pixel mapping and buffer usage. GPHY 11 and transformer 11a are configured for a link. A large-scale array of LED driver chip using GPHY technology requires a heavy volume of pins.
FIG. 2 is a schematic block diagram of an LED system 1′. Referring to FIG. 2, LED system 1′ includes a video processor 10, a transmitter 11, a receiver card 13, and a plurality of LED drivers 14. The receiver card 13 receives data from the transmitter 11 via a GPHY link. After receiving data designated thereto, the receiver card 13 distributes the received data to the plurality of LED drivers 14 attached thereto. Such data distribution necessitates pixel mapping to ensure that the initially transmitted data is received and reconstructed in desired order to display the final image from the video source on the LED display panel.
A large number of receiver cards and ports may present some problems. First, the receiver cards use transformer components 11a either in a transmitter port or a receiving port. The physical size of the transformer put a limit on the size of an ultrathin LED display panel. Second, a large number of transformers used as high frequency signal coupling devices in the port causes problematic electromagnetic radiation, such as electromagnetic interference (EMI). Third, a large number of receiver cards require a larger number of switching DC-DC converters, which are not only hard to integrate into the LED main display board but also create EMI. Further, a plurality of receiver cards and gigabit Ethernet ports attached thereto reside in an LED display panel and therefore increase the size of display. In addition, a large number of gigabit Ethernet ports and links significantly increase production costs of LED display panels. Accordingly, a display device, a method for transmitting data packet, and a light-emitting diode (LED) system that overcome the above described shortcomings are needed.